There are diverse processes for measuring inductivity/capacity values. Particularly with regard to a micro-processor measuring system for low inductivity/capacity values and, where appropriate, a high number of analog construction elements, there are numerous disadvantages. On the one side, the high number of analog components results in a requirement for lots of space and in a high cost. On the other hand, such measuring systems are sensitive to environmental influences, e.g. variations of temperatures. In addition, implementation with a micro-processor is expensive.
A typical measuring principle for capturing inductivities and capacities is to measure the time up to reaching the threshold value for the charge or discharge curve in the course of current or voltage progress. In this context, the disadvantage is that the measurement of low inductivity/capacity values is difficult. In addition, it is disadvantageous that tolerances of the threshold value switch, strongly impacting the measuring result. And finally, it is disadvantageous that the measuring spectrum with a low time constant is limited due to the resolution of the time counter.
An additional process is the tuning of resonance frequencies in order to ascertain the inductivity or capacity. This process is also suitable for low inductivity/capacity values. In this context, it is disadvantageous that low-tolerance components are required, on the one side, and the duration of measurement is relatively long, due to the time needed for the frequency passage (frequency sweep), on the other.
Should the electronic component feature a relatively low capacity or inductivity, the occurring signal flanks can be very steep as in e.g. the case of a step response. In order to measure at least one value of such a fast electrical signal flank, a fast analog-digital converter is required, which is relatively expensive.